it all add up you need not only transport food but clean water,drinking water, sanitary, and the whole caboodle I guess you didn't read your history well .
Back in roman time they run out of money because the cost of maintain garrison is so high. Well how about just now with Trump complaining left and right about allies taking advantage of US and doesn't contribute to cost of maintaining US army in Europe or Japan.
It cost Japan 2 billion per year to maintain 50,000 troop.That is just Japan contribution the total cost is much higher
NO it is not cheap. Ok Indian eat lentil but still it is expensive
That is the reason why Han dynasty doesn't maintain garrison in Xinjiang after defeating the HUN
Well the Indian soldier can disperse but after destruction of barrack and other support system like food storage, fuel and ammunition,water storage etc
How long you think they can hold down specially in winter time?